SPRINGFIELD TWP, Mercer County — A man was hurt when he took a hard landing while parachuting Saturday evening at the Grove City Airport, authorities said. The man, in his early 30s, suffered pain in his knee and back. He was flown by medical helicopter to an unknown Pittsburgh hospital. Authorities did not identify the man whose condition was not known this morning. The man was a student at Skydive Pennsylvania when he apparently lost control of his parachute while landing at the airport about 6:45 p.m. “The sky dive went as planned until the landing,” said Cecil Smith, owner of Skydive Pennsylvania, which operates a skydiving school and center next to the airport in Springfield Township. The Springfield Township Volunteer Fire Department and Superior Ambulance were called. “He was conscious, alert and oriented when we got there,” Doug Dick, a paramedic and EMS chief for the private Superior Ambulance Service, said of the injured man. “He did very well.” The man’s injuries were not considered serious. D